Raw water may be treated by any number of ways to obtain a final treated water product. However, the final treated water product may have a pH level unsuitable for commercial or consumer requirements. Typically, a final treated water product requires a pH level of less than 9. One method for lowering the pH level in water is to inject CO2 into the water by a direct gas feed system. The CO2 is passed through a diffusion system in a recarbonated basin. This diffusion system is commonly referred to as a bubbler. Another method for injecting carbon dioxide into water is to aspirate the carbon dioxide with a venturi. An apparatus using a venturi is sometimes also referred to as a diffuser.
In either method of introducing CO2 into water, the CO2 is introduced into a carrier solution to form a carbonic acid solution. To keep the CO2 in solution and prevent the formation of gas bubbles in the system, the carbonic acid solution is maintained at an elevated pressure. Diffusers are engineered to maintain the system pressure and to distribute the carbonic acid solution into the water being treated. As the pressurized carbonic acid solution is introduced into the water being treated, the CO2 expands and is released and mixed into the stream of water.
An example of a known diffuser is disclosed in my U.S. Pat. No. 5,487,835, the entire disclosure of which is incorporated herein by reference. In my '835 patent, the diffuser 71 has three rectangular sides defining a triangular prismatic structure. The diffuser 71 is inserted normal to the direction of flow of the water stream. The carbonic acid solution is passed through one end of the diffuser 71. While the carbonic acid solution is within the diffuser 71, the diffuser 71 maintains the elevated pressure of the carrier solution forcing the formation of carbonic acid and excess CO2, if any, to remain in the carbonic acid solution.
The diffuser 71 has a plurality of outlet holes on two of the rectangular sides. The plurality of holes face upstream while the third rectangular side faces down stream. The passing of the carbonic acid solution through the plurality of holes forces the CO2, if any, to be released into the stream of water to reduce the pH. The downstream positioning of the third side without the holes creates a vortex in the stream of water which creates additional mixing.